The answer is Newton's 1st law because the friction of the grass is an unbalanced force which changes the motion of the ball. Gravity pulls down on an object, while the normal force pushes up in the equal and opposite direction. This is even true when things are sitting still. Forces come in pairs, so when we send a baseball flying with a force of 50 Newtons, there is also a 50 Newton force acting on the baseball bat in the opposite direction. Newton’s 3rd Law: For every action there is an equal and opposite reaction. Lastly, we can solve for any of these variables if we are given two of them. It will also require more force to increase the acceleration of an object.
In other words, more massive objects require more force to accelerate the same distance as less massive ones. This law tells us that force is directly related to mass and acceleration. Newton’s 2nd Law: Force = mass x acceleration. In empty space, moving objects just keep going and going and going because there aren’t forces like air resistance or gravity to stop them! Motion usually stops due to the forces gravity, or friction. It will stay in motion until acted upon by an unbalanced force. An object at rest stays at rest until acted upon by an unbalanced force. Inertia is an objects tendency to resist changes in motion.
